Backfiring- MISFIRE

[TolerableOkay]

Dear All,


Couple of days ago, driving slowly but with harsh braking i had first issue with backfiring .loud and heavy while i was braking.

Then on the next day I had no issues what so ever, but then it came back and I noticed whenever it is harsh braking not even related on spead engine misfires and i can feel it though my brake pedal.

Could anyone have any ideas what could be the cause or how to solve occuring issue.?

Thanks

[axsaxoman]

not a clue -- but get car idling --then go under bonnet and wiggle all electrical connectors on sensors on engine and see if it does it

[TolerableOkay]

I recentley changed bulbs for headlights could connection there somehow interact with the problem thats occuring, I switched it back to old ones it is not as often - the issue as it used with new but it still happens as I dont think the bulbs are the issue

[TolerableOkay]

U mean while engine is running chech connections right?

[TolerableOkay]

So ,I read that that it can be due to Connectors, as you mentioned, or vacuum leaks, in worst case - fuel pump, or something dirty in fuel system.

So I will start with checking connectors and leaks

I will update you guys on the progress

[TolerableOkay]

I also noticed it does make a whistling slighlty up to 40mph, afterwards I cant hear it,

However all signs show that it might be vacuum leak, Today I had no issues at all while I was driving..
I'll update you guys have this issue solved by sunday as I plan to try to have a look and repair vac leak.

[axsaxoman]

If its an airleak on induction system --
a can of brake cleaner or easy start--- - spray around inlet manifold ,etc-- but not so it can be sucked in by air filter --if its running alters --then yes you have a leak

[TolerableOkay]

So I found out that brake fluid comes out of the rear right wheel, which makes me think, that wheel cylinder is gone.

in that case should i replace brake shoes as well? - i assume that yes.

My brake pedal is soft and goes to the floor and it is because there is not any pressure right?- so I need to change shoes and cylinder, bleed the system, and everything should be alright..

and in that case it wasnt backfire as the backfiring sound came out from the rear right but whistling noise because of air leak down there makes a lot of sense now...

please advise me on whats the best thing to do in these circumstances

[TolerableOkay]

Okay changed wheel cylinders for rears and brake shoes as well, all cleaned and bleeded,

after a day my brake pedal goes to the end, it is braking , and braking better than before service but it goes in to the ground more than clutch

what could be the issue?

[Spendyrx]

Okay changed wheel cylinders for rears and brake shoes as well, all cleaned and bleeded,

after a day my brake pedal goes to the end, it is braking , and braking better than before service but it goes in to the ground more than clutch

what could be the issue?

Is it bled properly?
Have you checked your brake lines for leaks?
Maybe take off back wheels and give the drums a good karate chop but it must be at an accute angle of 35°

[TolerableOkay]

Breaklines are not leaking

They bled it in service, I think i will go by and ask them to do it properly,

I will have a look on drums later on this week, thanks

[TolerableOkay]

Another thing, front brakes are warm after driving while rear ar cold as weather which means rears ar not working, front brakes are the only one that are working, however when i use handbrake, it is working fine

[Shadowslayerzz]

That's because the handbrake is on a separate cable going to the rear brakes, one cable each side, this sounds like either you have a leaking brake hose between servo in engine bay and rear brakes themselves or you have an air lock, check the brake lines for leaks by tracing back from engine bay to rear brakes, failing that you will need to bleed the brakes again to eliminate air locking as the problem.

[TolerableOkay]

I have checked couple of times nothing is leaking from brakes and the brake fluid reservoir is full as it used to be when i filled it up.

However between pump and servo there is a bit wet/sticky dirty area circled in picture around, could it be that air comes through there and that might need a change?

http://s9.postimg.org/6rsuek4vz/brakje.png

[Shadowslayerzz]

Hmmm, might be worth checking the flow from servo, this is a messy job though as you probably already know, I would unbolt the module from the servo, (unbolt the silver bit where it attaches to the black servo) then take resivour off which should just pull off of the grommet as they are push fit and check to see if there is any dirt or grime blocking anything, when you bled the brakes did you take the above part off of the servo? Only reason I ask is because if you don't pump some brake fluid through manually by pushing piston a couple times then you can get air locks, there is a guide on the faqs section on how to bleed brakes propperly if that's any use to you, also seen a very usefull video on YouTube that is spot on and he's working on a sack as well which is helpfull, hope this helps.

[TolerableOkay]

When the brakes were bled, the above part wasnt moved just topped up the fluid

[Shadowslayerzz]

That's why... You have an air lock mate, you need to do as said above otherwise you will get air locks.

[Shadowslayerzz]

Skip to 11:30 in this video and it shows you how to prime the cylinder
http://youtu.be/iLr4uV2pis4

[TolerableOkay]

but when I'm driving and press brake pedal 2-3 times it brakes really well

[TolerableOkay]

So you suggest- changing master cylinder , but wont i need to bleed brakes again after changing it? or this should solve the problem.

I checked around servo and master cylinder, its actually just paint coming off and not wet because of brake fluid as I thought before, it coulld be wet before as it was rainy day when i checked before, and i am 100% sure now that here are no leaks as double checked this evening.

I just never had issue with brakes before.

[Synister]

Pumping the brakes will build up pressure in the system and will allow your brakes to work 'better' but not properly.

Either buy an ezbleed brake bleeding kit (or similar) and do it again yourself or else bring it to a competent mechanic whom will do it properly. The guy that bled your brakes last time shouldn't have let the car leave the garage like that.

[TolerableOkay]

Bled them properly and now everything is fine, just might need to adjust rear right brake as shoes were changed, but I think i saw a post how to do it somewhere here, thanks guys for advice, that wast master cylinder fault as it is braking and pedal is not going to floor anymore

[Shadowslayerzz]

Glad this is sorted, good lad :y: